JP4053134B2

JP4053134B2 - Inverted hydraulic shock absorber

Info

Publication number: JP4053134B2
Application number: JP15590598A
Authority: JP
Inventors: 博美福田
Original assignee: Yamaha Motor Co Ltd
Current assignee: Yamaha Motor Co Ltd
Priority date: 1998-06-04
Filing date: 1998-06-04
Publication date: 2008-02-27
Anticipated expiration: 2018-06-04
Also published as: JPH11351308A

Description

【０００１】
【発明の属する技術分野】
本発明はストラットタイプの倒立式油圧緩衝器に関する。
【０００２】
【従来の技術】
ストラットタイプの倒立式油圧緩衝器として、従来、例えば特開平１０−９３２６号公報に記載されたものがある。これは、ストラットチューブの上下にダンパチューブ支持部を設け、それらの上下にさらにオイルシールを設け、上記ダンパチューブ, ストラットチューブ及びオイルシールによって囲まれた空間をオイル溜まりとしている。
【０００３】
上記従来の緩衝器では、路面の凹凸に応じてダンパチューブがストラットチューブ内を相対的に摺動し、該摺動に伴って上記オイル溜まり内の油が潤滑油として作用して、上記摺動がスムーズに行なわれる。
【０００４】
【発明が解決しようとする課題】
ところが上記従来の緩衝器では、全体の外径があまり大きくならないようにするために、ストラットチューブの内径寸法をダンパチューブの外径寸法に出来るだけ近づける必要があり、上記オイル溜まりの容積が小さくなる傾向がある。その結果、オイル溜まり内の潤滑油量を十分に確保できず、潤滑油の劣化が早くなり、また、潤滑油が有する軸受部の冷却機能も不十分であるという問題がある。
【０００５】
本発明は、上記問題に鑑みてなされたもので、全体の外径を大きくすることなく潤滑油量を増加でき、潤滑性能や冷却性能を向上できる倒立式油圧緩衝器を提供することを課題としている。
【０００６】
【課題を解決するための手段】
請求項１の発明は、下端が閉塞された外筒内に複数の軸受部材を介して上，下端が閉塞されピストンを内蔵するシリンダを上方から摺動自在に挿入し、上記ピストンに接続され、上記シリンダの下端から下方に突出するピストンロッドの下端を上記外筒の下端閉塞部に固定してなる倒立式油圧緩衝器において、上記シリンダの外周面と外筒の内周面との隙間に設けられた間隙油室と、上記外筒の底部に設けられ潤滑油を貯留する貯油室と、該貯油室と上記間隙油室とを連通する連通路と、該油圧緩衝器の伸縮動作により上記貯油室と間隙油室との間で潤滑油を循環させる循環機構とを備え、上記軸受部材を上記間隙油室内に位置させたことを特徴としている。
【０００７】
請求項２の発明は、請求項１において、上端が上記シリンダと外筒との隙間内の上記軸受部材近傍に位置し、下端が上記外筒の貯油室内に位置するよう固定された円筒状の中間筒を設け、該中間筒の外周面と上記外筒の内周面とで囲まれた空間を上記貯油室から上記間隙油室に潤滑油を供給する供給側連通路とし、上記中間筒の内周面と上記シリンダの外周面とで囲まれた空間を上記間隙油室から上記貯油室に潤滑油を戻す戻り側連通路としたことを特徴としている。
【０００８】
請求項３の発明は、請求項２において、上記循環機構は、上記中間筒の上端に取り付けられ、上記シリンダの相対的下降行程時に潤滑油の貯油室側から間隙油室側への供給のみを許容し、上記シリンダの相対的上昇行程時に潤滑油の間隙油室側から貯油室側への戻りのみを許容する流動調整弁を備えていることを特徴としている。
【０００９】
請求項４の発明は、請求項２において、上記循環機構は、上記貯油室と上記供給側連通路との境界部に設けられ、上記シリンダの相対的下降行程時に潤滑油の貯油室側から間隙油室側への供給のみを許容する逆止弁と、上記中間筒の上端に取り付けられ、上記シリンダの相対的上昇行程時に潤滑油の間隙油室側から貯油室側への戻りを許容する流動調整弁とを備えていることを特徴としている。
【００１０】
【発明の作用効果】
請求項１の発明によれば、シリンダと外筒との隙間に軸受部材を内蔵するように間隙油室を設け、該間隙油室と外筒の底部の潤滑油を貯留する貯油室との間で潤滑油を循環させるようにしたので、緩衝器全体の外径を大きくすることなく容易に貯油室の容量を大きくでき、そのため上記間隙油室ひいては軸受部材への潤滑油量を十分確保することができ、潤滑性能を向上することができる。また潤滑油量が十分であることから、潤滑油による冷却性能も十分に確保できる。
【００１１】
請求項２の発明によれば、中間筒を、上端部がシリンダの外周面と外筒の内周面との間の間隙油室に位置し、下部が貯油室に位置するように配置固定し、該中間筒と外筒との間隙を供給側連通路とし、該中間筒とシリンダとの隙間を戻り側連通路としたので、外筒の外側に連通路を設けることなく潤滑油の循環が可能となり、連通路を外筒の外側に設けた場合のような他の車載部品との干渉を回避でき、また外観の見栄えも向上することができる。
【００１２】
請求項３の発明によれば、緩衝器の収縮により上記シリンダが相対的に下降すると、貯油室の圧力が上昇し、潤滑油が貯油室側から流動調整弁を介して間隙油室側に供給される。また緩衝器の伸びにより上記シリンダが相対的に上昇すると、貯油室の圧力が下降し、潤滑油が間隙油室側から流動調整弁を介して貯油室側に戻る。このようにして緩衝器の伸縮に伴って潤滑油が貯油室と間隙油室との間で循環し、上記潤滑性能，冷却性能の向上が実現される。
【００１３】
この場合に、流動調整弁を、中間筒の上端、つまり高所に設けたので、摺動により生じた金属粉等が流動調整弁に侵入しにくく、該流動調整弁の作動が長期にわたって確保される。また、流動調整弁を潤滑油の供給，戻りの両方の調整機能を有するものとしたので、部品点数が少なくて済み、該調整弁の小型化，コスト削減を図ることができる。
【００１４】
請求項４の発明によれば、緩衝器の収縮により上記シリンダが相対的に下降すると、貯油室の圧力が上昇し、潤滑油が貯油室側から逆止弁を介して間隙油室に供給される。また緩衝器の伸びにより上記シリンダが相対的に上昇すると、貯油室の圧力が下降し、潤滑油が間隙油室側から流動調整弁を介して貯油室側に戻る。このようにして緩衝器の伸縮に伴って潤滑油が貯油室と間隙油室との間で循環し、上記潤滑性能，冷却性能の向上が実現される。
【００１５】
この場合に潤滑油の供給，戻り調整機能を貯油室の逆止弁と中間筒の流動調整弁とに分離して持たせたので、両機能の特性を個別的に自由に設定でき、設定上の自由度を拡大できる。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を添付図面に基づいて説明する。
図１〜図５は本発明の一実施形態によるストラットタイプの倒立式油圧緩衝器を説明するための図であり、図１は上記緩衝器の断面図、図２, ３, ４は上記緩衝器の要部断面図、図５は上記緩衝器に用いられる部材の例を説明するため要部断面図である。
【００１７】
図１において、１は本発明のストラットタイプの倒立式油圧緩衝器を示しており、該緩衝器１は、下端が底部材４により閉塞され、ブラケット２を介して車輪（不図示）側に取り付けられるアウタチューブ（外筒）３と、上記底部材４に下端が固定され、上方に延びるピストンロッド５と、該ピストンロッド５の上端部に固定されたピストン６と、該ピストン６が摺動自在に嵌挿され、上記ピストンロッド５の下端部が下方に突出するシリンダ（インナチューブ）７とを備えている。
【００１８】
上記シリンダ７は、アウタチューブ３の内周面に所定の軸方向間隔を開けて圧入された軸受部材（ブッシュ）８, ９を介して上記アウタチューブ３内に摺動自在に嵌挿されており、該アウタチューブ３の上端部には、シリンダ７との間をシールするシール部材２２が装着されている。なお、軸受部材８，９の厚みは２ｍｍ程度であり、また上下の軸受部材８，９間には潤滑油を表面張力による毛細管現象により上昇させるためジャバラ状のスペーサを介在させても良い。また上記アウタチューブ３の上端開口にはシリンダ７の外周との間をシールするためのシール部材２２が装着されている。
【００１９】
上記シリンダ７の下端開口は底板７ａで閉塞され、上端開口はジョイントボルト１２のボス部１２ａで閉塞されている。そしてシリンダ７内空間は、上記ピストン６により上側，下側油室Ｓ１, Ｓ２に画成されており、該ピストン６には、作動油が上記油室Ｓ１, Ｓ２間を流動することにより減衰力を発生させる減衰機構を備えている。
【００２０】
またシリンダ７の底部内周には、上記ピストンロッド５が油密に挿通されるロッドガイド１０が固定リング７ｂ，７ｂの範囲内で若干上下移動可能に取り付けられている。上記ロッドガイド１０は、上記ピストンロッド５に摺接するブッシュ１３と両者間をシールするオイルシール１４を備えている。また上記ロッドガイド１０の上面には最大伸長時に上記ピストン６の下面のストッパ１７に当接して衝撃を和げるためのリバウンドラバー１６が配設さられている。
【００２１】
さらにまた、上記外筒３の底部には最大収縮時に上記シリンダ７の底板７ａに当接して衝撃を和げるためのバンプラバー１９が配設されている。このバンプラバー１９は、円筒体の軸方向２箇所にくびれ部１９ａ，１９ａを有するゴム製のもので、上記ピストンロッド５の下端に固定リング５ａにより固定されたベース板５ｂ上に当接している。また該ベース板５ｂはピストンロッド５の下方突出部に固定ナット５ｄを締め込むことにより上記底板４とでシール用オーリング５ｃを挟持し、これにより潤滑油の洩れを防止している。
【００２２】
また上記アウタチューブ３内には、これより小径の円筒状の中間筒２１が配設されている。該中間筒２１の上端部２１ａは上記シリンダ７の外周面とアウタチューブ３の内周面との間に位置しており、また該中間筒２１の下端部２１ｂはアウタチューブ３の底板４近傍まで下方に延び、環状のベースバルブ板２７の外周面に油密に接続固定されている。上記中間筒２１の上端部２１ａには上記シリンダ７の外周面及びアウタチューブ３の内周面に摺接する流動調整弁２３が装着されており、該流動調整弁２３と上記シリンダ７の外周面，上記アウタチューブ３の内周面及び上記シール部材２２で囲まれた空間が間隙油室Ｓ３となっている。
【００２３】
上記アウタチューブ２の底部は潤滑油を貯留するための貯油室Ｓ４となっている。該貯油室Ｓ４と上記間隙油室Ｓ３とは、上記中間筒２１の外周面と上記外筒３の内周面との隙間により構成される供給側連通路ａ、及び該中間筒２１の内周面と上記シリンダ７の外周面との隙間により構成される戻り側通路ｂを介して連通可能となっている。
【００２４】
また上記貯油室Ｓ４と上記供給側通路ａとの間には逆止弁２９を有する上記ベースバルブ板２７が介在されている。上記逆止弁２９は、同一円周上に複数貫通形成された連通孔２７ａの下側開口をばね板製で環状の板弁２８により開閉可能に構成されている。この逆止弁２９は、潤滑油の上記貯油室Ｓ４側から上記供給側連通路ａ側への流れのみを許容する。なお、上記板弁２８はその内周縁が、上記ベースバルブ板２７の外周に嵌着された固定リング２８ａにより上記ベースバルブ板２７の下面に配置固定されている。
【００２５】
上記流動調整弁２３は、ゴム等の弾性体製のテーパ筒状のものであり、外周面の軸方向中間部に形成された嵌合溝２３ｃが上記中間筒２１の上端部２１ａに嵌着され、接着剤等により固定されている。該流動調整弁２３の下縁部である戻り側弁部２３ａの内周面はシリンダ７の外周面７ｃに押圧状態で摺接しており、また上縁部である供給側弁部２３ｂの外周面はアウタチューブ３の内周面３ｃに押圧状態で摺接している。
【００２６】
上記戻り側弁部２３ａは、上記シリンダ７の相対的上昇により上記貯油室Ｓ４内の圧力が間隙油室Ｓ３の圧力より所定値以上低くなると、潤滑油が間隙油室Ｓ３から貯油室Ｓ４側に戻るように、つまり上記外周面７ｃとの間に隙間が開くよう変形する。また上記供給側弁部２３ｂは、上記シリンダ７の相対的下降により上記貯油室Ｓ４内の圧力が上記間隙油室Ｓ３の圧力より所定値以上高くなると潤滑油が貯油室Ｓ４側から間隙油室Ｓ３側に供給されるように、つまり上記内周面３ｃとの間に隙間が開くように変形する。このようにして上記貯油室Ｓ４と間隙油室Ｓ３との間で潤滑油を循環させる循環機構３１が構成されている。
【００２７】
次に本実施形態における動作及び作用効果を説明する。
まず、本実施形態の緩衝器１における減衰動作について説明する。車輪が路面の突部に乗り上げると、図示しない緩衝ばねが圧縮されるとともに、上記アウタチューブ３が相対的に上昇すると同時に上記ピストン６がシリンダ７内で相対的に上昇し、作動油が上側油室Ｓ１から下側油室Ｓ２に流動しその際に圧縮時減衰力が発生する。また車輪が路面の凹部に来ると上記アウタチューブ３が相対的に下降すると同時に上記ピストン６が相対的に下降し、作動油が下側油室Ｓ２から上側油室Ｓ１に流動しその際に伸時減衰力が発生する。
【００２８】
上記減衰動作において、上記シリンダ７とアウタチューブ３との相対的伸縮動作は両者の間に介設された軸受部材８，９を介して行われ、該軸受部材８，９とシリンダ７との摺動面には、貯油室Ｓ４内に油面Ｗをなすように貯留されている潤滑油が循環機構３１の動作により循環供給される。
【００２９】
まず緩衝器１の収縮により相対的に上記アウタチューブ３が上昇し上記シリンダ７が下降すると、貯油室Ｓ４の圧力が上昇し、該貯油室Ｓ４内の潤滑油が逆止弁２９を押し開いて供給側連通路ａに入り、該連通路ａを通り流動調整弁２３の供給側弁部２３ｂを押し開いて間隙油室Ｓ３内に供給される。この場合、戻り側弁部２３ａは貯油室Ｓ４の圧力により摺動面７ｃに圧接しており、これにより間隙油室Ｓ３内の圧力が上昇し、該間隙油室Ｓ３に供給された潤滑油は下側軸受部材９とシリンダ７との摺動面を通って上側の軸受部材８とシリンダ７との摺動面に達する。下側軸受部材９と上側軸受部機材８との間には上述のスペーサが設けられていることにより潤滑油が容易に上昇し、従って潤滑油が両方の軸受部材８，９の摺動面に確実に供給され、潤滑性能が向上する。
【００３０】
一方、緩衝器１の伸びにより上記シリンダ７が相対的に上昇すると、貯油室Ｓ４の圧力が下降し、間隙油室Ｓ３内の潤滑油が流動調整弁２３の戻り側弁部２３ａを押し開いて流下し、貯油室Ｓ４側に戻る。このようにして緩衝器１の伸縮に伴って潤滑油が貯油室Ｓ４と間隙油室Ｓ３との間で循環し、軸受部材８，９の摺動面に十分な潤滑油が供給されて潤滑性能が向上し、また十分な潤滑油量により冷却性能が向上する。
【００３１】
また、貯油室Ｓ４と供給側連通路ａとの間に、緩衝器１の収縮により上記シリンダ７が相対的に下降して貯油室Ｓ４の圧力が上昇すると開き、逆にシリンダ７が相対的に上昇して貯油室Ｓ４の圧力か低下すると閉じる逆止弁２９を介在させたので、上記供給側連通路ａ内の潤滑油が貯油室Ｓ４側に逆流することはなく、上記潤滑油の循環をより一層確実に行うことができる
【００３２】
さらにまた、中間筒２１を、上端部２１ａがシリンダ７の外周面とアウタチューブ３の内周面との間の間隙油室Ｓ３部分に位置し、下端部２１ｂが貯油室Ｓ４部分に位置するように配置固定し、該中間筒２１とアウタチューブ３との間隙を供給側連通路ａとし、該中間筒２１とシリンダ７との隙間を戻り側連通路ｂとしたので、アウタチューブ３の外側に連通路を設けることなく潤滑油の循環が可能となり、連通路をアウタチューブの外側に設けた場合のような他の車載部品との干渉を回避でき、また外観の見栄えも向上することができる。
【００３３】
上記実施形態では、流動調整弁２３を、戻り側弁部２３ａ及び供給側弁部２３ｂを備えたものとしたが、これは図５に示すように、戻り側弁部２３ａのみを備え、間隙油室Ｓ３と供給側連通路ａとを常時連通させるようにした流動調整弁２３′であっても良い。この場合には、貯油室Ｓ４と供給側連通路ａとの間に設けられた上記逆止弁２９が上記実施形態における供給側弁部２３ｂの機能を果たすこととなる。従って、図５の流動調整弁２３′を採用した場合には、上記逆止弁２９は必須となる。なお、図４に示す流動調整弁２３を採用した場合には、上記逆止弁２９は必ずしも備えなくても良い。
【図面の簡単な説明】
【図１】本発明の一実施形態によるストラット型倒立式油圧緩衝器の断面側面図である。
【図２】上記緩衝器の底部の断面側面図である。
【図３】上記緩衝器のベースバルブ部分の要部断面側面図である。
【図４】上記緩衝器の流動調整弁部分の要部断面側面図である。
【図５】上記流動調整弁の変形例の要部断面側面図である。
【符号の説明】
１油圧緩衝器
３アウタチューブ（外筒）
４底板（下端閉塞部）
５ピストンロッド
６ピストン
７シリンダ７
８，９軸受部材
２１中間筒
２３，２３′流動調整弁
２９逆止弁
３１循環機構
Ｓ３間隙油室
Ｓ４貯油室
ａ，ｂ供給側，戻り側連通路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a strut type inverted hydraulic shock absorber.
[0002]
[Prior art]
As a strut type inverted hydraulic shock absorber, there is a conventional one disclosed in, for example, JP-A-10-9326. In this structure, damper tube support portions are provided above and below the strut tube, oil seals are further provided above and below them, and a space surrounded by the damper tube, the strut tube and the oil seal is used as an oil reservoir.
[0003]
In the conventional shock absorber, the damper tube slides relatively in the strut tube according to the unevenness of the road surface, and the oil in the oil reservoir acts as a lubricating oil along with the sliding, and the sliding Is performed smoothly.
[0004]
[Problems to be solved by the invention]
However, in the conventional shock absorber, in order to prevent the overall outer diameter from becoming too large, it is necessary to make the inner diameter dimension of the strut tube as close as possible to the outer diameter dimension of the damper tube, and the volume of the oil reservoir is reduced. Tend. As a result, there is a problem that the amount of lubricating oil in the oil reservoir cannot be sufficiently secured, the deterioration of the lubricating oil is accelerated, and the cooling function of the bearing portion possessed by the lubricating oil is insufficient.
[0005]
The present invention has been made in view of the above problems, and it is an object of the present invention to provide an inverted hydraulic shock absorber capable of increasing the amount of lubricating oil without increasing the overall outer diameter and improving the lubricating performance and cooling performance. Yes.
[0006]
[Means for Solving the Problems]
The invention of claim 1 is inserted into the outer cylinder closed at the lower end via a plurality of bearing members, and a cylinder containing the piston with the lower end closed is slidably inserted from above and connected to the piston. In the inverted hydraulic shock absorber in which the lower end of the piston rod protruding downward from the lower end of the cylinder is fixed to the lower end closing portion of the outer cylinder, provided in a gap between the outer peripheral surface of the cylinder and the inner peripheral surface of the outer cylinder. The oil storage chamber is formed by a gap oil chamber formed therein, an oil storage chamber that is provided at the bottom of the outer cylinder and stores lubricating oil, a communication passage that communicates the oil storage chamber and the gap oil chamber, and an expansion / contraction operation of the hydraulic shock absorber. A circulation mechanism for circulating lubricating oil between the chamber and the gap oil chamber, and the bearing member is positioned in the gap oil chamber .
[0007]
The invention of claim 2 is a cylindrical shape according to claim 1, wherein the upper end is positioned in the vicinity of the bearing member in the gap between the cylinder and the outer cylinder, and the lower end is fixed so as to be positioned in the oil storage chamber of the outer cylinder. An intermediate cylinder is provided, and a space surrounded by the outer peripheral surface of the intermediate cylinder and the inner peripheral surface of the outer cylinder serves as a supply-side communication path for supplying lubricating oil from the oil storage chamber to the gap oil chamber. A space surrounded by the inner peripheral surface and the outer peripheral surface of the cylinder is a return-side communication path that returns the lubricating oil from the gap oil chamber to the oil storage chamber.
[0008]
According to a third aspect of the present invention, in the second aspect, the circulation mechanism is attached to an upper end of the intermediate cylinder, and only supplies the lubricating oil from the oil storage chamber side to the gap oil chamber side during the relative downward stroke of the cylinder. A flow regulating valve is provided that permits and allows only the return of the lubricating oil from the gap oil chamber side to the oil storage chamber side during the relative upward stroke of the cylinder.
[0009]
According to a fourth aspect of the present invention, in the second aspect, the circulation mechanism is provided at a boundary portion between the oil storage chamber and the supply-side communication path, and the clearance from the oil storage chamber side of the lubricating oil is provided during the relative downward stroke of the cylinder. A check valve that allows only supply to the oil chamber side, and a flow that is attached to the upper end of the intermediate cylinder and that allows the return of the lubricating oil from the gap oil chamber side to the oil storage chamber side during the relative upward stroke of the cylinder And a regulating valve.
[0010]
[Effects of the invention]
According to the first aspect of the present invention, the gap oil chamber is provided so as to incorporate the bearing member in the gap between the cylinder and the outer cylinder, and between the gap oil chamber and the oil storage chamber for storing the lubricating oil at the bottom of the outer cylinder. Since the lubricating oil is circulated in the tank, it is possible to easily increase the capacity of the oil storage chamber without increasing the outer diameter of the entire shock absorber, and therefore to ensure a sufficient amount of lubricating oil to the gap oil chamber and thus the bearing member. The lubrication performance can be improved. Further, since the amount of the lubricating oil is sufficient, the cooling performance by the lubricating oil can be sufficiently ensured.
[0011]
According to the invention of claim 2, the intermediate cylinder is arranged and fixed so that the upper end portion is located in the gap oil chamber between the outer peripheral surface of the cylinder and the inner peripheral surface of the outer cylinder, and the lower portion is located in the oil storage chamber. Since the gap between the intermediate cylinder and the outer cylinder is a supply side communication path and the gap between the intermediate cylinder and the cylinder is a return side communication path, the lubricating oil can be circulated without providing a communication path outside the outer cylinder. It is possible to avoid interference with other in-vehicle components as in the case where the communication path is provided outside the outer cylinder, and the appearance can be improved.
[0012]
According to the invention of claim 3, when the cylinder is relatively lowered due to contraction of the shock absorber, the pressure of the oil storage chamber is increased, and the lubricating oil is supplied from the oil storage chamber side to the gap oil chamber side through the flow regulating valve. Is done. When the cylinder rises relatively due to the extension of the shock absorber, the pressure in the oil storage chamber decreases, and the lubricating oil returns from the gap oil chamber side to the oil storage chamber side via the flow regulating valve. In this way, the lubricating oil circulates between the oil storage chamber and the gap oil chamber as the shock absorber expands and contracts, and the above-described lubrication performance and cooling performance are improved.
[0013]
In this case, since the flow regulating valve is provided at the upper end of the intermediate cylinder, that is, at a high place, metal powder generated by sliding hardly enters the flow regulating valve, and the operation of the flow regulating valve is ensured for a long time. The In addition, since the flow regulating valve has both the lubrication oil supply and return regulating functions, the number of parts can be reduced, and the regulating valve can be reduced in size and cost.
[0014]
According to the invention of claim 4, when the cylinder is relatively lowered due to the contraction of the shock absorber, the pressure of the oil storage chamber is increased, and the lubricating oil is supplied from the oil storage chamber side to the gap oil chamber via the check valve. The When the cylinder rises relatively due to the extension of the shock absorber, the pressure in the oil storage chamber decreases, and the lubricating oil returns from the gap oil chamber side to the oil storage chamber side via the flow regulating valve. In this way, the lubricating oil circulates between the oil storage chamber and the gap oil chamber as the shock absorber expands and contracts, and the above-described lubrication performance and cooling performance are improved.
[0015]
In this case the supply of lubricating oil, since the return adjusting function gave separated into a flow control valve of the check valve and the intermediate cylinder of the oil storage chamber, can be freely set the properties of both the functional individually, on setting Can be expanded.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 5 are views for explaining a strut type inverted hydraulic shock absorber according to an embodiment of the present invention. FIG. 1 is a sectional view of the shock absorber, and FIGS. 2, 3, and 4 are shock absorbers. FIG. 5 is a fragmentary cross-sectional view for explaining an example of a member used in the shock absorber.
[0017]
In FIG. 1, reference numeral 1 denotes a strut type inverted hydraulic shock absorber according to the present invention. The shock absorber 1 is closed at the lower end by a bottom member 4 and attached to a wheel (not shown) side via a bracket 2. The outer tube (outer cylinder) 3, the lower end of the bottom member 4 is fixed, the piston rod 5 extends upward, the piston 6 is fixed to the upper end of the piston rod 5, and the piston 6 is slidable. And a cylinder (inner tube) 7 in which the lower end portion of the piston rod 5 protrudes downward.
[0018]
The cylinder 7 is slidably inserted into the outer tube 3 via bearing members (bushings) 8 and 9 which are press-fitted into the inner peripheral surface of the outer tube 3 at a predetermined axial interval. A sealing member 22 that seals between the outer tube 3 and the cylinder 7 is attached to the upper end portion of the outer tube 3. The bearing members 8 and 9 have a thickness of about 2 mm, and a bellows-like spacer may be interposed between the upper and lower bearing members 8 and 9 in order to raise the lubricating oil by capillary action due to surface tension. A seal member 22 for sealing the outer periphery of the cylinder 7 is attached to the upper end opening of the outer tube 3.
[0019]
The lower end opening of the cylinder 7 is closed by a bottom plate 7 a, and the upper end opening is closed by a boss portion 12 a of the joint bolt 12. The internal space of the cylinder 7 is defined by the piston 6 in upper and lower oil chambers S1 and S2, and the hydraulic fluid flows between the oil chambers S1 and S2 in the piston 6 so that a damping force is generated. A damping mechanism for generating
[0020]
A rod guide 10 through which the piston rod 5 is inserted in an oil tight manner is attached to the inner periphery of the bottom of the cylinder 7 so as to be slightly movable up and down within the range of the fixing rings 7b and 7b. The rod guide 10 includes a bush 13 that is in sliding contact with the piston rod 5 and an oil seal 14 that seals between them. A rebound rubber 16 is disposed on the upper surface of the rod guide 10 so as to come into contact with the stopper 17 on the lower surface of the piston 6 and relieve an impact when the rod guide 10 is fully extended.
[0021]
Furthermore, a bump rubber 19 is disposed at the bottom of the outer cylinder 3 to abut against the bottom plate 7a of the cylinder 7 when the maximum contraction occurs and to soften the impact. The bump rubber 19 is made of rubber having constricted portions 19a and 19a at two axial positions of the cylindrical body, and abuts on a base plate 5b fixed to the lower end of the piston rod 5 by a fixing ring 5a. . Further, the base plate 5b clamps a sealing nut 5d in the downward projecting portion of the piston rod 5 to sandwich the sealing O-ring 5c with the bottom plate 4, thereby preventing leakage of lubricating oil.
[0022]
A cylindrical intermediate cylinder 21 having a smaller diameter is disposed in the outer tube 3. The upper end 21 a of the intermediate cylinder 21 is located between the outer peripheral surface of the cylinder 7 and the inner peripheral surface of the outer tube 3, and the lower end 21 b of the intermediate cylinder 21 extends to the vicinity of the bottom plate 4 of the outer tube 3. It extends downward and is connected and fixed to the outer peripheral surface of the annular base valve plate 27 in an oil-tight manner. The upper end portion 21a of the intermediate cylinder 21 is fitted with a flow regulating valve 23 that is in sliding contact with the outer circumferential surface of the cylinder 7 and the inner circumferential surface of the outer tube 3, and the outer circumferential surface of the flow regulating valve 23 and the cylinder 7, A space surrounded by the inner peripheral surface of the outer tube 3 and the seal member 22 is a gap oil chamber S3.
[0023]
The bottom of the outer tube 2 serves as an oil storage chamber S4 for storing lubricating oil. The oil storage chamber S4 and the gap oil chamber S3 include a supply side communication path a formed by a gap between the outer peripheral surface of the intermediate cylinder 21 and the inner peripheral surface of the outer cylinder 3, and the inner periphery of the intermediate cylinder 21. Communication is possible via a return-side passage b formed by a gap between the surface and the outer peripheral surface of the cylinder 7.
[0024]
The base valve plate 27 having a check valve 29 is interposed between the oil storage chamber S4 and the supply side passage a. The check valve 29 is made of a spring plate and can be opened and closed by an annular plate valve 28 at a lower opening of the communication hole 27a formed in a plurality of holes on the same circumference. This check valve 29 allows only the flow of the lubricating oil from the oil storage chamber S4 side to the supply side communication path a side. The inner peripheral edge of the plate valve 28 is disposed and fixed on the lower surface of the base valve plate 27 by a fixing ring 28 a fitted on the outer periphery of the base valve plate 27.
[0025]
The flow regulating valve 23 has a tapered cylindrical shape made of an elastic material such as rubber, and a fitting groove 23c formed in an axially intermediate portion of the outer peripheral surface is fitted into the upper end portion 21a of the intermediate tube 21. It is fixed with an adhesive or the like. The inner peripheral surface of the return side valve portion 23a, which is the lower edge portion of the flow regulating valve 23, is in sliding contact with the outer peripheral surface 7c of the cylinder 7, and the outer peripheral surface of the supply side valve portion 23b, which is the upper edge portion. Is in sliding contact with the inner peripheral surface 3c of the outer tube 3 in a pressed state.
[0026]
When the pressure in the oil storage chamber S4 becomes lower than the pressure in the gap oil chamber S3 by a predetermined value or more due to the relative rise of the cylinder 7, the return side valve portion 23a causes the lubricating oil to move from the gap oil chamber S3 to the oil storage chamber S4 side. It deform | transforms so that it may return, ie, a clearance gap may be opened between the said outer peripheral surfaces 7c. Further, when the pressure in the oil storage chamber S4 becomes a predetermined value or more higher than the pressure in the gap oil chamber S3 due to the relative lowering of the cylinder 7, the supply side valve portion 23b causes the lubricating oil to flow from the oil storage chamber S4 side to the gap oil chamber S3. It deform | transforms so that a clearance gap may open between the said inner peripheral surfaces 3c, that is, to be supplied to the side. In this way, the circulation mechanism 31 for circulating the lubricating oil between the oil storage chamber S4 and the gap oil chamber S3 is configured.
[0027]
Next, operations and effects in this embodiment will be described.
First, the damping operation in the shock absorber 1 of the present embodiment will be described. When the wheel rides on the protrusion on the road surface, a buffer spring (not shown) is compressed, and the outer tube 3 relatively rises, and at the same time, the piston 6 rises relatively in the cylinder 7 so that the working oil is the upper oil. Flow from the chamber S1 to the lower oil chamber S2 causes a damping force during compression. Further, when the wheel comes into the concave portion of the road surface, the outer tube 3 is relatively lowered, and at the same time, the piston 6 is relatively lowered, so that the hydraulic oil flows from the lower oil chamber S2 to the upper oil chamber S1 and extends at that time. Damping force is generated.
[0028]
In the damping operation, the relative expansion and contraction operation between the cylinder 7 and the outer tube 3 is performed via the bearing members 8 and 9 interposed therebetween, and the sliding between the bearing members 8 and 9 and the cylinder 7 is performed. Lubricating oil stored in the oil storage chamber S4 so as to form the oil surface W is circulated and supplied to the moving surface by the operation of the circulation mechanism 31.
[0029]
First, when the outer tube 3 rises relatively due to the contraction of the shock absorber 1 and the cylinder 7 descends, the pressure in the oil storage chamber S4 rises, and the lubricating oil in the oil storage chamber S4 pushes the check valve 29 open. It enters the supply side communication passage a, passes through the communication passage a, pushes the supply side valve portion 23b of the flow regulating valve 23, and is supplied into the gap oil chamber S3. In this case, the return-side valve portion 23a is in pressure contact with the sliding surface 7c due to the pressure in the oil storage chamber S4, thereby increasing the pressure in the gap oil chamber S3, and the lubricating oil supplied to the gap oil chamber S3 is The sliding surface between the lower bearing member 9 and the cylinder 7 reaches the sliding surface between the upper bearing member 8 and the cylinder 7. Since the above-described spacer is provided between the lower bearing member 9 and the upper bearing member 8, the lubricating oil easily rises, and therefore the lubricating oil is applied to the sliding surfaces of both the bearing members 8 and 9. Reliable supply and improved lubrication performance.
[0030]
On the other hand, when the cylinder 7 is relatively raised by the extension of the shock absorber 1, the pressure in the oil storage chamber S4 is lowered, and the lubricating oil in the gap oil chamber S3 pushes the return side valve portion 23a of the flow regulating valve 23 open. It flows down and returns to the oil storage chamber S4 side. Thus, as the shock absorber 1 expands and contracts, the lubricating oil circulates between the oil storage chamber S4 and the gap oil chamber S3, and sufficient lubricating oil is supplied to the sliding surfaces of the bearing members 8 and 9 to provide a lubricating performance. In addition, the cooling performance is improved by a sufficient amount of lubricating oil.
[0031]
Further, the cylinder 7 is relatively lowered by the contraction of the shock absorber 1 between the oil storage chamber S4 and the supply side communication passage a, and opens when the pressure of the oil storage chamber S4 is increased. Since a check valve 29 is interposed that closes when the pressure in the oil storage chamber S4 rises and decreases, the lubricating oil in the supply-side communication passage a does not flow back to the oil storage chamber S4 side, and the lubricating oil is circulated. Can be performed more reliably [0032]
Furthermore, the intermediate cylinder 21 is positioned such that the upper end portion 21a is located in the gap oil chamber S3 portion between the outer peripheral surface of the cylinder 7 and the inner peripheral surface of the outer tube 3, and the lower end portion 21b is located in the oil storage chamber S4 portion. The gap between the intermediate cylinder 21 and the outer tube 3 is used as a supply-side communication path a, and the gap between the intermediate cylinder 21 and the cylinder 7 is used as a return-side communication path b. Lubricating oil can be circulated without providing a communication path, and interference with other in-vehicle components, such as when the communication path is provided outside the outer tube, can be avoided, and the appearance can be improved.
[0033]
In the above embodiment, the flow regulating valve 23 is provided with the return side valve portion 23a and the supply side valve portion 23b. However, as shown in FIG. It may be a flow regulating valve 23 ′ in which the chamber S 3 and the supply side communication passage a are always in communication. In this case, the check valve 29 provided between the oil storage chamber S4 and the supply side communication path a functions as the supply side valve portion 23b in the embodiment. Therefore, when the flow regulating valve 23 'of FIG. 5 is adopted, the check valve 29 is essential. When the flow regulating valve 23 shown in FIG. 4 is adopted, the check valve 29 is not necessarily provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view of a strut type inverted hydraulic shock absorber according to an embodiment of the present invention.
FIG. 2 is a cross-sectional side view of the bottom of the shock absorber.
FIG. 3 is a cross-sectional side view of an essential part of a base valve portion of the shock absorber.
FIG. 4 is a cross-sectional side view of an essential part of a flow regulating valve portion of the shock absorber.
FIG. 5 is a cross-sectional side view of an essential part of a modified example of the flow regulating valve.
[Explanation of symbols]
1 Hydraulic shock absorber 3 Outer tube (outer cylinder)
4 Bottom plate (lower end closing part)
5 Piston rod 6 Piston 7 Cylinder 7
8, 9 Bearing member 21 Intermediate cylinder 23, 23 'Flow regulating valve 29 Check valve 31 Circulating mechanism S3 Gap oil chamber S4 Oil storage chamber a, b Supply side, return side communication passage

Claims

Inserted into the outer cylinder with its lower end closed through a plurality of bearing members, a cylinder with its upper and lower ends closed and containing a piston is slidably inserted from above, connected to the piston, and downward from the lower end of the cylinder. In an inverted hydraulic shock absorber in which the lower end of the projecting piston rod is fixed to the lower end closing portion of the outer cylinder, a gap oil chamber provided in a gap between the outer peripheral surface of the cylinder and the inner peripheral surface of the outer cylinder; An oil storage chamber that is provided at the bottom of the outer cylinder and stores lubricating oil, a communication passage that communicates the oil storage chamber and the gap oil chamber, and an expansion and contraction operation of the hydraulic shock absorber, between the oil storage chamber and the gap oil chamber. An inverted hydraulic shock absorber, wherein the bearing member is positioned in the gap oil chamber .

2. A cylindrical intermediate cylinder having a fixed upper end positioned in the vicinity of the bearing member in a gap between the cylinder and the outer cylinder and a lower end positioned in an oil storage chamber of the outer cylinder. A space surrounded by the outer peripheral surface of the cylinder and the inner peripheral surface of the outer cylinder serves as a supply-side communication path for supplying lubricating oil from the oil storage chamber to the gap oil chamber, and the inner peripheral surface of the intermediate cylinder and the cylinder An inverted hydraulic shock absorber characterized in that a space surrounded by an outer peripheral surface is a return side communication path for returning lubricating oil from the gap oil chamber to the oil storage chamber.

3. The circulation mechanism according to claim 2, wherein the circulation mechanism is attached to an upper end of the intermediate cylinder, allows only supply of lubricating oil from the oil storage chamber side to the gap oil chamber side during the relative downward stroke of the cylinder, An inverted hydraulic shock absorber provided with a flow regulating valve that allows only the return of lubricating oil from the gap oil chamber side to the oil storage chamber side during a general ascent stroke.

3. The circulation mechanism according to claim 2, wherein the circulation mechanism is provided at a boundary portion between the oil storage chamber and the supply side communication passage, and only supplies the lubricating oil from the oil storage chamber side to the gap oil chamber side during the relative downward stroke of the cylinder. And a flow adjustment valve that is attached to the upper end of the intermediate cylinder and allows the return of the lubricating oil from the gap oil chamber side to the oil storage chamber side during the relative upward stroke of the cylinder. An inverted hydraulic shock absorber characterized by that.